1. Field of the Invention
This invention relates to a method and to a device for protecting film-mounted integrated circuits (micropacks) against destruction due to electrostatic charges when handling those circuits.
2. Description of the Prior Art
The sensitivity of integrated circuits in MOS technology to electrostatic charges is known. Such an electrostatic charge can be caused and can lead to the destruction of the circuits when handling the circuits themselves or the assemblies that are equipped with these circuits. However, even given circuits which are constructed in a technology different than MOS, a hazard to the circuits is not excluded. The hazard of electrostatic charge destruction increases in significance given an increasing integration density of such circuits. A general protection of integrated circuits against electrostatic charging is therefore necessary. This is especially true for circuits which are mounted in a film carrier and which are handled and processed as micropacks.
The standard method of protecting integrated circuits against electrostatic charging consists of short-circuiting or grounding the circuits. It is known, for example, given film-mounted circuits, to extend the track connections of the circuits beyond the outer contacting region and to combine the connections in one or more short-circuit points and to in turn connect these short-circuit points to a grounding track running along the entire film length.
The connections to the short-circuit points must be separated for the electrical check of an integrated circuit and thus must be re-connected to the grounding track for further manipulation after the check. This can occur, for example, by cutting out the short-circuit points before the check, and after the check, reclosing the points with a solder rivet. Because of the small dimensions of the cut-out short-circuit points, this method requires high-precision work when re-connecting the points and, with current technology, can only be manually executed.
It has therefore already been proposed to design the track connections of the integrated circuits such that a conductive surface is provided in the track between the short-circuit point and the grounding track, that surface connecting these two to one another, being separated therefrom at two sides and being disposed above a cut-out in the film and dimensioned such that, after the third side is cut, it can be folded over the fourth side such that it covers all conductors leading to the short-circuit point. Although this measure has already led to very good results, it cannot be applied everywhere where, because of the multitude of connections of the integrated circuit, space no longer exists for the accommodation of such a surface.